1. Field of the Invention
The teachings provided herein are directed to a high specific gravity intragastric device, a method for delivering the device in a subject, and a method for treating obesity in the subject.
2. Description of the Related Art
Obesity is a worldwide problem that needs an effective remedy. More than one third of the adult population of the United States, for example, is considered to be obese, and, it's estimated that 27% of men and 38% of women are obese in Europe. A person can be considered “obese” if their body mass index (BMI) is greater than 30 kg/m2, where the BMI can be defined as the person's weight in kg divided by the person's height in m2. In fact, a person is considered “morbidly obese” if their BMI is greater than 35 kg/m2. Unfortunately, approximately 23 million of the 72 million adults in the US are morbidly obese.
The problem is that obesity is linked to numerous chronic health conditions that include, for example, hypertension, hyperlipidemia, sleep apnea, type-2 diabetes, and heart disease. In addition to an obviously decreased life expectancy, obesity-associated conditions significantly increase the length of hospital stays, and make a substantial impact on overall healthcare costs, to the extent that, in late 2005, the Center for Disease Control and Prevention estimated that about 27% of all health care costs in the US are due to inactivity and excess body weight. The same year, Medicare estimated a 35% increase in costs for obese patients over the age of 70 than their non-obese counterparts. And, it's not just a cost issue for healthcare providers and insurers—it can get very personal to the obese individual. For example, there are many adverse psychosocial aspects of obesity that include alterations in feelings of well-being, a reduced quality of life, a lower income earning potential, and the social stigmatization that is commonly realized with obesity. Moreover, the decrease in lifespan associated with obesity is comparable to the effects of smoking, where a BMI greater than 25 is correlated to a reduction in lifespan by 2-4 years in persons in the age range of 30-35. A BMI above 40 has been shown to reduce lifespan by 8-10 years. Vascular disease relating to heart attacks and strokes, hypertension, and type-2 diabetes, are common causes of health conditions and mortality among the obese. Obesity is an epidemic, and society remains overwhelmed and cannot effectively deal with this serious, growing threat to the Nation's health.
Currently, a common belief is that dieting and exercise is the only true answer. Although certainly effective beyond dispute, one problem is that diet and exercise have not been the answer for most patients. Failure rates are high, and few patients actually lose enough weight to produce meaningful health benefits. One answer to the problem has been obesity surgery, acclaimed as being the most effective intervention available in the US and including, for example, restrictive, malabsorptive, and combination techniques. One problem with such surgeries is that that are currently indicated only for patients with a BMI greater than 35 kg/m2. Another problem is that the costs are high, easily exceeding $20,000. As such, the public and healthcare community has been slow to adopt obesity surgery for several reasons such as, for example, a lack of insurance. Other reasons include a fear of the procedure, as well as patient and provider attitudes regarding obesity. There were 220,000 obesity surgeries in the US in 2008, and the rate of growth is over 30% per year, representing less than 2% of all obese US persons that could quality for this procedure, showing that other methods are clearly needed. Accordingly, new and effective procedures that are less costly and less invasive would be appreciated by those of skill in the art.
Currently, intragastric implant devices are used to avoid obesity surgeries. These devices are typically free floating intragastric balloons that reside in the upper stomach and have volumes ranging from about 400 cc to about 800 cc. These devices are known for creating a feeling of “fullness,” increasing the time it takes to digest a meal, and having a treatment period of 6 months or less. Unfortunately, the treatment period is limited by a number of factors that include, for example, (i) expansion of the stomach around the balloon which re-establishes the normal gastric clearance and removes the feeling of fullness experienced by the patient; (ii) leakage of the balloon creating a loss of volume; and (iii) complete failure of the balloon itself. Such large devices also have some post-placement effects that can include, for example, gastric wall contractions that create repeated episodes of projectile vomiting, early explant of the device, and life-threatening gastric perforations in some cases. Another less serious problem, although embarrassing, is a noticeable bad breath, a condition induced by the growth of plaque on the larger current intragastric devices resulting in halitosis. The use of proton pump inhibitors, or PPIs, commonly prescribed for use with the current, state-of-the-art larger balloons to decrease side-effects, adds to the bad breath issue, and it also adds cost to the treatment, as well as additional risk to the patient from overmedication. Other devices have been suggested for use in the lower, more muscular portion of the stomach known as the pyloric antrum to help control appetite. The objective of placing a device in the lower stomach is to increase distention of the antral walls during meals. Inducing an antral wall distention helps induce early feelings of fullness or gastric discomfort, leading to consumption of less volume and reduced caloric intake levels. These devices have been limited to having some sort of anchoring means, such as a tail that extends past the pylorus, an anchoring flange, or some mechanism of fastening to gastrointestinal tissue.
Each of the antrum-based devices have problems that generally either relate to adverse consequences from having (a) a portion of the device that passes through the pylorus and into the duodenum; and/or, (b) a fixation means to prevent migration in the stomach. Problems from (a) can include, for example, a retraction and entanglement of a tube that extends into the duodenum, as well as providing a means for infectious materials, such as a virus or bacteria normally destroyed by stomach acids, to enter the small intestine. Problems from (b) can include blockage of the pylorus and interruption of the otherwise normal stomach functions. Other problems from both (a) and (b) can include, for example, the formation of ulcers due to tissue irritation. As a result, these antrum-based devices under development have not been accepted by the medical community.
As can be seen from the above description of the problems and the state-of-the-art practices in the field of intragastric devices, a person of skill in the art would appreciate a gastric implant that (i) is more affordable for patients; (ii) is less feared by patients than obesity surgery; (iii) functions in the antrum region of the stomach to avoid limited treatment times associated with stomach expansion around current intragastric balloons; (iv) avoids passage of any part of the device past the pylorus to avoid retraction and entanglement in the stomach, ulcers, and passage of infectious materials into the duodenum; (v) is free floating in the stomach to avoid problems associated with fixation of the device, as well as promote normal gastric function; and, (vi) can be at least substantially leakproof when compared to state-of-the art intragastric balloons.